Re: [PATCH V2 bpf-next 2/2] selftests/bpf: add selftest for bpf_task_get_cgroup

From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Ratheesh Kannoth <rkannoth@marvell.com>
Cc: Jose Fernandez <josef@netflix.com>,
	Alexei Starovoitov <ast@kernel.org>,
	 Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	 Martin KaFai Lau <martin.lau@linux.dev>,
	Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
	 Yonghong Song <yonghong.song@linux.dev>,
	John Fastabend <john.fastabend@gmail.com>,
	 KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	 Jiri Olsa <jolsa@kernel.org>, bpf <bpf@vger.kernel.org>,
	 LKML <linux-kernel@vger.kernel.org>,
	 "open list:KERNEL SELFTEST FRAMEWORK"
	<linux-kselftest@vger.kernel.org>,
	Tycho Andersen <tycho@tycho.pizza>
Subject: Re: [PATCH V2 bpf-next 2/2] selftests/bpf: add selftest for bpf_task_get_cgroup
Date: Sun, 17 Mar 2024 20:15:31 -0700	[thread overview]
Message-ID: <CAADnVQ+9s3yCR2eLL=b_Mqrv37VB_mywa9cnbE=+X_E8VcFBKA@mail.gmail.com> (raw)
In-Reply-To: <20240318031025.GA1312616@maili.marvell.com>

On Sun, Mar 17, 2024 at 8:10 PM Ratheesh Kannoth <rkannoth@marvell.com> wrote:
>
> On 2024-03-16 at 21:52:41, Jose Fernandez (josef@netflix.com) wrote:
> > This patch adds a selftest for the `bpf_task_get_cgroup` kfunc. The test
> > focuses on the use case of obtaining the cgroup ID of the previous task
> > in a `sched_switch` tracepoint.
> >
> > The selftest involves creating a test cgroup, attaching a BPF program
> > that utilizes the `bpf_task_get_cgroup` during a `sched_switch`
> > tracepoint, and validating that the obtained cgroup ID for the previous
> > task matches the expected cgroup ID.
> >
> > Signed-off-by: Jose Fernandez <josef@netflix.com>
> > Reviewed-by: Tycho Andersen <tycho@tycho.pizza>
> > ---
> > V1 -> V2: Refactor test to work with a cgroup pointer instead of the ID
> >
> >  .../bpf/prog_tests/task_get_cgroup.c          | 58 +++++++++++++++++++
> >  .../bpf/progs/test_task_get_cgroup.c          | 37 ++++++++++++
> >  2 files changed, 95 insertions(+)
> >  create mode 100644 tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c
> >  create mode 100644 tools/testing/selftests/bpf/progs/test_task_get_cgroup.c
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c b/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c
> > new file mode 100644
> > index 000000000000..67ed65d0c461
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c
> > @@ -0,0 +1,58 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +// Copyright 2024 Netflix, Inc.
> > +
> > +#include <test_progs.h>
> > +#include <cgroup_helpers.h>
> > +#include "test_task_get_cgroup.skel.h"
> > +#include <unistd.h>
> > +
> > +#define TEST_CGROUP "/test-task-get-cgroup/"
> > +
> > +void test_task_get_cgroup(void)
> > +{
> > +     struct test_task_get_cgroup *skel;
> > +     int err, fd;
> > +     pid_t pid;
> > +     __u64 cgroup_id, expected_cgroup_id;
> > +     const struct timespec req = {
> > +             .tv_sec = 1,
> > +             .tv_nsec = 0,
> > +     };
> Reverse Xmas tree.

NO. We don't do it in bpf trees.